Download (2 elements) Ionic Compounds

Do First
Actions: Turn in your lab to the drawer
What is wrong with the drawn molecules
below?
1.
2.
O=O
F-F
Agenda
1. Notes
2. Practice
Naming and Writing Ionic and
Covalent Compounds
What to write on your periodic table:
1+
1VE
2+
2VE
3+
3- 2- 13VE 4VE 5VE 6VE 7VE
0
8VE
NAMING Binary (2 elements) Ionic Compounds
• Ionic compounds are made of a
metal/nonmetal combination
• The metal (positive ion) is written first
followed by the nonmetal (negative ion)
• A binary compound always ends with the
suffix “-ide”
NAMING Binary (2 elements) Ionic Compounds
• For example, NaCl:
– This compound contains two elements: sodium and
chlorine
– Sodium is the cation and chlorine is the anion
– The oxidation number (charge) of sodium (Na) is 1+
– The oxidation number (charge) of chlorine (Cl) is 1– Name the metal (cation) first, and then the nonmetal
(anion) with the ending changed to “ide”
– NaCl = Sodium Chloride
– Some tricky ones include:
• Nitrogen = Nitride; Phosphorus = Phosphide;
Oxygen = Oxide; Sulfur = Sulfide
WRITING Ionic Compounds – Criss Cross Method
• Used to write ionic formulas using oxidation numbers
(charge)
• Steps
1. Write the symbol for each element
2. Assign the oxidation number (charge) for each
element in the upper right hand corner of the symbol
3. Cross the NUMBER, NOT the (+) or (-)
sign
4. Check the TOTAL charges. A molecule is neutral – the
positive and negative charges are equal
WRITING Ionic Compounds – Criss Cross Method
• For example: Magnesium Chloride
– Magnesium = Mg; Chlorine = Cl
– Mg2+; Cl1-
2+
–Mg ;
1Cl
– Mg1Cl2 – BUT, don’t leave “1” as a subscript... Just
leave it out… so…
– MgCl2
WRITING Ionic Compounds – Criss Cross Method
• For example: Magnesium Oxide
– Magnesium = Mg; Oxygen = O
– Mg2+; O2-
2+
–Mg ;
2O
– Mg2O2 – BUT, if the numbers can be simplified, do so!
– MgO
WRITING Ionic Compounds – Criss Cross Method
• For example: Magnesium Phosphide
– Magnesium = Mg; Phosphorus = P
– Mg2+; P3-
2+
–Mg ;
– Mg3P2
3P
Transition Metals
• Most transition metals form cations with
different charges
• A Roman Numeral is used to indicate the charge
– Fe2+ = iron (II)
– Fe3+ = iron (III)
• The Roman Numeral MUST be used in the name!
– FeO = iron (II) oxide
– Fe2O3 = Iron (III) oxide
Transition Metals
• EXCEPTIONS!!!
– Silver (Ag) is ALWAYS 1+ and Zinc (Zn) is ALWAYS 2+.
Do NOT use roman numerals with these elements
– Tin (Sn) and Lead (Pb) from group 14 can have a 2+
OR 4+ charge. YOU MUST ALWAYS use a roman
numeral with these elements.
Practice
• Complete the white section of your worksheet
WRITE THE FORMULA AND NAME THE COMPOUND
DYL
1. In naming an ionic compound, does the
anion or cation written first?
2. When in naming do you use Roman
Numerals?
Polyatomic Ions
• A polyatomic ion consists of more than one
element covalently bonded together that has
a charge
• The name of the ion is not changed when it
forms a compound
• Examples of polyatomic ions include:
– OH-1 = Hydroxide It’s important to think of these as
“Packages”!!!!!!!
– SO4-2 = Sulfate
– (A common polyatomic ions chart has been given
to you)
Writing Formulas for Compounds
with Polyatomic Ions
• Write the chemical formula for lithium acetate
– Lithium = Li+1; Acetate = C2H3O2-1
– Cross the number NOT the charge!
–Li+1 C2H3O2-1
– LiC2H3O2
Writing Formulas for Compounds
with Polyatomic Ions
• Write the chemical formula for sodium
carbonate
– Sodium= Na+1; Carbonate = CO3-2
– Cross the number NOT the charge!
–Na+1 CO3-2
– Na2CO3
Writing Formulas for Compounds
with Polyatomic Ions
• Write the chemical formula for aluminum
bicarbonate
– aluminum= Al+3; Bicarbonate = HCO3-1
– Cross the number NOT the charge!
–Al+3 HCO3-1
– Be careful!!!!!! If you have more than one
polyatomic ion, put parentheses around it before
you assign it a number!
– Al(HCO3)3
Naming Covalent Compounds
• Covalent bonds occur between two or more
nonmetals
• NO ions are formed; therefore, there is no
need to write charges (or roman numerals)
• Covalently bonded molecules may have
different whole number combinations of the
same elements
Naming Covalent Compounds
• In naming covalent
compounds
– The 1st element only
gets a prefix IF
THERE IS MORE
THAN ONE ATOM
– The 2nd element
ALWAYS gets a prefix
and ALWAYS ends in
“-ide”
• Prefixes
 1 = mono
 2 = di
 3 = tri
 4 = tetra
 5 = penta
 6 = hexa
 7 = hepta
 8 = octa
 9 = non
 10 = deca
Practice
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SO3
ICl3
PBr5
C3H6
CI4
PCl3
N2O3
PF5
CCl4
CO2
Sulfur Trioxide
Iodine Trichloride
Phosphorous pentabromide
tricarbon hexahydride
carbon tetraiodide
Phosphorus trichloride
dinitrogen trioxide
phosphorus pentafluoride
carbon tetrachloride
carbon dioxide
Practice
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Disulfur trichloride
Diphosphorus trioxide
Carbon diselenide
Carbon tetraiodide
Diarsenic trisulfide
Dinitrogen pentoxide
Tetraphosphorus decoxide
Selenium hexafluoride
Disilicon hexabromide
Diboron monosilicide
S2Cl3
P2O3
CSe2
CI4
As2S3
N2O5
P4O10
SeF6
Si2Br6
B2Si